This book began its life as a casual conversation in early October 2014. Both of us were postgraduate students at that time, writing our doctoral theses and taking a break from our fieldwork in mainland China. We bumped into each other in Admiralty, a business district in downtown Hong Kong that was then occupied by angry protesters. Though we were no strangers to the spectacle of mass protests in our hometown, the Umbrella Movement truly surprised us with its sheer scale and burst of energy. As often happens in academic dialogues, we agreed that we should start studying these unfolding events; and we did. In the following days, we designed a survey, assembled a team, and distributed the surveys across the three protest camps. Time was of the essence as it seemed likely that the police would clear out these camps at any minute. Thanks to our team’s efforts, we were able to complete the data collection. We never anticipated that the occupation would continue for another two months. Nor did we foresee that the movement would become a key turning point in Hong Kong’s history and politics.

Since then, we closely followed protest events in what was known to international observers as the ‘city of protests’. We dug into Hong Kong’s history of protests and continued to conduct surveys and ground observations whenever there were major rallies or demonstrations. We interviewed politicians, activists, protest participants, government officials, and ordinary citizens. Our research deepened the conviction that this dynamic laboratory of protests could contribute important insights to the scholarship of contentious politics. As exemplified by the Umbrella Movement, the intensity and innovative forms of Hong Kong’s popular contention have often resonated with mass mobilizations happening globally since the early 2010s, including the Arab Spring uprisings, the Global Occupy Movement, the Spanish Indignados, and the Maidan Revolution in Ukraine.

In 2019, the eruption of the Anti-Extradition Movement once again brought this liberal enclave on the fringe of China into the global limelight, making it arguably the most extensively reported protest event of the twenty-first century. As students of contentious politics, we readily deployed our research toolkits and studiously documented the unfolding events. This time, we were again surprised – not only by the scale of participation in the movement but also by its resilience, despite the lack of a centralized leadership. International observers would soon recognize similar dynamics in mass mobilizations emerging globally in the ensuing months in 2019 and 2020, from Belarus to Chile, France to Lebanon, Sudan to Iraq, Indonesia to Thailand, and even in the United States. Although these mobilizations were sparked by various causes, they shared a common thread of spontaneity and a conspicuous absence of leadership. The tactical repertoire on display also bore striking similarities, with many tactics evidently originating from Hong Kong. This is why we felt a compelling need to produce a comprehensive account of Hong Kong’s protest trajectory and its gradual shift from organized contention to leaderful mobilization. We hope that this book will yield comparative insights for contentious politics scholars. For those interested in Hong Kong and China, we hope that this book offers a systematic account of the sociopolitical evolution of this semi-autonomous city, leading to the implementation of the National Security Law in 2020. While times and circumstances have undoubtedly shifted, our belief in the value of research and scholarship remains as strong as ever.

Academic research often feels like a solitary journey, but co-authoring this book has made it much less so. Being co-authors meant we were constantly exchanging our ideas and challenging each other. There were innumerable moments of intense debates and disagreements, but each time we were able to come to a consensus and ultimately refined our ideas. This book is a product of these intellectual dialogues and our friendship. Although we took the lead on different chapters, we spent a lot of time critiquing, cross-examining, and rewriting each other’s work. Both of us equally contributed to this book and regard each other as co-first authors.